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Hydractiniais a colonial marine hydroid that shows remarkable biological properties, including the capacity to regenerate its entire body throughout its lifetime, a process made possible by its adult migratory stem cells, known as i-cells. Here, we provide an in-depth characterization of the genomic structure and gene content of twoHydractiniaspecies,Hydractinia symbiolongicarpusandHydractinia echinata, placing them in a comparative evolutionary framework with other cnidarian genomes. We also generated and annotated a single-cell transcriptomic atlas for adult maleH. symbiolongicarpusand identified cell-type markers for all major cell types, including key i-cell markers. Orthology analyses based on the markers revealed thatHydractinia’s i-cells are highly enriched in genes that are widely shared amongst animals, a striking finding given thatHydractiniahas a higher proportion of phylum-specific genes than any of the other 41 animals in our orthology analysis. These results indicate thatHydractinia’s stem cells and early progenitor cells may use a toolkit shared with all animals, making it a promising model organism for future exploration of stem cell biology and regenerative medicine. The genomic and transcriptomic resources forHydractiniapresented here will enable further studies of their regenerative capacity, colonial morphology, and ability to distinguish self from nonself.
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Cellular‐resolution gene expression mapping reveals organization in the head ganglia of the gastropod, Berghia stephanieae
Abstract Gastropod molluscs such asAplysia,Lymnaea, andTritoniahave been important for determining fundamental rules of motor control, learning, and memory because of their large, individually identifiable neurons. Yet only a small number of gastropod neurons have known molecular markers, limiting the ability to establish brain‐wide structure–function relations. Here we combine high‐throughput, single‐cell RNA sequencing with in situ hybridization chain reaction in the nudibranchBerghia stephanieaeto identify and visualize the expression of markers for cell types. Broad neuronal classes were characterized by genes associated with neurotransmitters, like acetylcholine, glutamate, serotonin, and GABA, as well as neuropeptides. These classes were subdivided by other genes including transcriptional regulators and unannotated genes. Marker genes expressed by neurons and glia formed discrete, previously unrecognized regions within and between ganglia. This study provides the foundation for understanding the fundamental cellular organization of gastropod nervous systems.
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- Award ID(s):
- 2227963
- PAR ID:
- 10577598
- Publisher / Repository:
- Journal of Comparative Neurology
- Date Published:
- Journal Name:
- Journal of Comparative Neurology
- Volume:
- 532
- Issue:
- 6
- ISSN:
- 0021-9967
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/cne.25628
